1. Field of the Invention
The present invention relates to novel glycine derivatives of low skin irritancy and high foaming power, processes for producing the same, and cleanser compositions containing such glycine derivatives.
Further, the present invention relates to other glycine derivatives which are useful as intermediates for synthesizing the above-mentioned glycine derivatives and are themselves useful as cleansers, processes for producing the same, and cleanser compositions containing such glycine derivatives.
Furthermore, the present invention relates to a method of washing skin or hair using such a cleanser composition, i.e., an use of the cleanser composition.
The cleanser compositions of the present invention exhibit excellent foaming, are free from sliminess and stickiness and exhibit excellent foam breaking during rinsing, have reduced irritancy toward the skin and are excellent in storage stability.
2. Discussion of the Background
In recent years, it has become necessary to minimize the effects that surfactants to be used as cleansers on the environment. In other words, it has become necessary that the surfactants be excellent in biodegradability and safety, and exhibit reduced irritancy toward the skin and eyes. Various surfactants such as acylated amino acids, imidazoline surfactants, alkyl phosphate salts, betaine surfactants and saccharide surfactants have been developed and employed as surfactants meeting these requirements.
Although these surfactants are excellent in environmental protection and safety, their foaming powers and detergencies are generally unsatisfactory. Therefore, the surfactants that are generally used for, e.g., a shampoo, a body cleanser, a tableware detergent are still anionic surfactants such as higher fatty acid salts (soaps), alkyl sulfates (AS), polyoxyethylene alkyl ether sulfates (ES) and alkyl sulfonates, and the aforementioned surfactants are only used as auxiliaries.
When, for example, soap is used for skin cleansing, soap scum (Ca salt of higher fatty acid) is formed and adheres to the skin during rinsing, so that the smoothness of the skin surface is remarkably lowered to result in squeakiness and stiffness. When an alkyl sulfate or an alkyl sulfonate is used for skin cleansing, it is poor in foam breaking and causes a problem with respect to comport in use such as sliminess and stickiness, though it does not result in squeakiness and stiffness.
Therefore, various auxiliaries such as oils, e.g., a higher alcohol, and auxiliary cleansers are contained in cleanser compositions such as shampoos, body cleansers and tableware detergents. However, the empolyment of such auxiliaries leads to a degradation of the detergency, foaming power, comfort in use and the like, so that the types and the amounts of the auxiliaries which can be used are subject to various restraints. Thus, it has been difficult to obtain cleanser compositions having satisfactory performances.
Under these circumstances, cleanser compositions each containing an anionic surfactant of an acylimino dibasic acid type have been proposed [see Japanese Patent Publication-A Nos. 54-30207 (published on Mar. 6, 1979), 5-117139 (published on May 14, 1993) and-6-80987 (published on Mar. 22, 1994)]. Although these cleanser compositions are improved in detergency, foaming power and comfort in use, as compared with those in the prior art, they have a drawback in that the storage stability at, especially, low temperatures is poor, because the anionic surfactants of the acylimino dibasic acid type are derivative of an iminodiacetic acid.
Consequently, the development of surfactants which are excellent in environmental protection and safety, exhibit high foaming power and detergency, are excellent the comfort in use and can be used for various purposes is strongly demanded in the art. There also remains a need for such surfactants which exhibit excellent storage stability when used as one component of a cleanser composition.